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United States Patent | 6,043,936 |
Large | March 28, 2000 |
A diffractive structure (100) has a substantially planar substrate (1). A set of facets (2) is formed in or on said substrate (1), the plane or planes in which the facets (2) lie being arranged at a non-zero angle to the plane of the substrate (1). Each facet (2) has a diffraction grating (5) formed thereon. The diffractive structure (100) will produce color over a wide range of viewing and illumination angles.
Inventors: | Large; Timothy Andrew (Cambridge, GB) |
Assignee: | De La Rue International Limited (London, GB) |
Appl. No.: | 077460 |
Filed: | June 9, 1998 |
PCT Filed: | December 6, 1996 |
PCT NO: | PCT/GB96/03016 |
371 Date: | June 9, 1998 |
102(e) Date: | June 9, 1998 |
PCT PUB.NO.: | WO97/21121 |
PCT PUB. Date: | June 12, 1997 |
Dec 06, 1995[GB] | 9524862 |
Current U.S. Class: | 359/572; 264/1.31; 264/2.5; 359/569; 359/900 |
Intern'l Class: | G02B 005/18; B29D 011/00 |
Field of Search: | 359/566,569,570,567,8,529,530,900,572,571 264/1.31,2.5 |
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5161057 | Nov., 1992 | Johnson | 359/566. |
5299061 | Mar., 1994 | Wakatake | 359/530. |
5682265 | Oct., 1997 | Farn et al. | 359/571. |
5905571 | May., 1999 | Butler et al. | 356/328. |
Foreign Patent Documents | |||
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404356001 | Dec., 1992 | JP | 359/566. |
E. G. Loewen, "Diffraction Gratings for Spectroscopy", Journal of Physics E Scientific Instruments vo. 3, pp. 953-961, Dec. 1970. T. Shiono et al., "Computer-Controlled Electron-Beam Writing System for Thin Film Micro-Optics", Journal of Vacuum Science & Technology: Part B, vol. 5, No. 1, pp. 33-36, Feb. 1987. Klumpp et al., "Anisotropic Etching for Optical Gratings", Sensors and Actuators A, vol. A51, pp. 77-80, Oct. 1995. |